Controller for electric motors



Feb. 7, 1928. 1,658,242

R. B. HUNTER v CONTROLLER FOR ELECTRIC MOTORS Filed JulyG, 1926 Patented Feb. 7, 1928 UNITED, STATES 1,658,242 PATENT OFFICE.

RICHARD B. HUNTER, F SHOREWOOD, WISCONSIN, ASSIGNOR TO THE CUTLER-HAM- MER MFG. CO., OF MILWAUKEE,

WISCONSIN, A CORPORATION OF WISCONSIN.

CONTROLLER FOR ELECTRIC MOTORS.

Application filed July 6,

This invention relates to controllers for electric motors, and more particularly to controllers for motor operated woodworking machines and the like.- Woodworking machines for tenoning or mortising ordinarily comprise a plurality of cutter motors, each cutter being adapted to perform an operation upon a piece of wood simultaneously with the other cutters; and a: common feed motor which pushes the Wood past the several cutters. It a cutter breaks or fails to out due to a knot or other obstacle in the wood, it is highly desirable that the cutter motor aifected and the feed motor be is stopped as quickly as possible.

An object of the invention is to provide simple and etficient means for accomplishment of the aforementioned desirable result, among others.

Another object is to provide means for insuring against operation of the feed motor during starting of one or more of the cutter motors.

Another object is to provide automatic electrical control means for efli'ecting stopping of the feed motor jointly with one or more of the cutter motors under predetermined conditions.

Another object is to provide manual control means for efiecting starting or stopping of the several motors jointly or individually, but subject to control by suitable electrical interlocks.

. Other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of various modifications without departing from the spirit and scope of my invention as defined in the appended claims.

In the drawing, M designates a feed motor adapted to efiect passage of a piece of wood through a woodworking machine (not shown), and M and M designate the cutter. motors. It is to be understood that the number of cutter motors included in the control system may be increased or decreased if desired. Said motors are adapted to be supplied with energy froma suitable source, as

indicated at lines L L and L line L being directly connected to terminals T respectively, whereas connection of lines L and L with terminals T and T 'of the wvinding of switch S 1926. Serial No. 120,694.

respective motors is controlled by electroresponsive switches S, S and S Individual push-button stations P, P and P are provided for control of the energizing circuits of the respective electroresponsive switches S, S and S said energizing circuits being also subject to control by suitable overload relays 0L, 0L and 0L which may be of the delayed action type. Relays OL controlling-the energizing circuit of switch S may be omitted if desired.

The energizing circuit of switch S is also subject to control by normally closed aum'liary contacts 10 of an electroresponsive relay R; whereas the energizing circuit of relay R is subject to control by normally open auxiliary contacts 11 of switch S in conjunction with auxiliary contacts 12 or 13 of switches S and S respectively. Contacts 12 and 13 are of the transient closing type; that is to say they are normally open in the opened or closed positions of switches S and S respectively, but are adapted to be temporarily closed during opening or closing of the latter.

Switches S, S and S are also provided with normally open auxiliary contacts l4, l5 and 16 adapted when closed to provide maintaining circuits for said switches, respectively. Normally closed overload relay contacts 17 18 are included in the energizing circuit of switch S, as aforedescribed; whereas normally closed overload relay contacts 19, 20 and 21, 22 are included in the energizing circuits of switches S and S respectively. Push-button station P comprises normally open contacts 23 adapted when closed to efiect starting of motor M, and normally closed contacts 24 adapted when opened to effect stopping of said motor. Push-button stations P and P similarly comprise normally open contacts 25 and 27 and normally closed contacts 26 and 28 for effecting starting and stopping of motors M and M respectively.

The operation of the control system now be described. Upon closure of pushbutton switch 27' an energizing circuit is completed for switch S said circuit extend ing from line L by conductor 29 throu h said switch 27, by conductor 30 through the normally closed contacts of push-button switch 28, by conductor 31 through the by conductor 82 through the normally closed contacts 22 and 21 of overload relays L and thence conductor through auxiliary contacts 11 through the right-hand overload relay coil of switch S, by conductors 46 and 47 through to line L Switch S thereupon closes to the right-hand overload. relay coil, and complete the line connections for motor M thence to line L Relay R immediately said lineflconnections being obvious. Durcloses and provides a maintaining circuit ing closure of switch S auxiliary contacts for itself, said maintaining circuit extending 13 are temporarily closed for a purpose herefrom line L by conductors 48 and 49 inafter described. Also upon closure of through the main contacts 50 of said rela switch S auxiliary contacts 16 thereof are by conductors 51 and 44 through-the win adapted to provide a maintaining circuit ing of relay R, and thence to line L as pre- 7 therefor, said circuit extending from line viously traced. Relay R in closing effects L by conductor 33 through the left-hand opening of its normally closed auxiliary overload relay coil, through the left-hand contacts 10 thereby interrupting the aforemain contacts of switch S through auxlldescribed maintaining circult of switch S, iary contacts 16, by conductor 34 throu h whereby the latter is opened to effect stop- 8 push-button switch 28, and thence to line i ping of motor M. Moreover, switch S in as previously traced. The power and conopening eifects opening of its auxiliary control circuits for motor M and any other tacts 11 thereby interrupting the aforecutter motor which might be included in described maintaining circuit of relay R the system are exactly like those described which thereupon assumes its normally open with reference to motor M and hence furposition. ther discussion thereof is deemed unneces- Obviously, if motors M, M and M are ary. in operation an overload upon motor M With switches S and S closed in the will effect interruption of the maintaining manner aforedescribed, closure of switch S circuits of switches S and S for simultanemay be effected by closure of push-button ous stopping of motors M and M, as aforeswitch 23, which completes an energizing described in connection with motors M and circuit extending from line L by conductor M. If either of the cutter motors M or M 35 through said switch 23, by conductor 36 is stopped due to an overload the other through normally closed push-button switch cutter motor will be left running, but no 24, by conductor 37 through the winding of harm will result because the feed motor switch S, by conductor 38 through normally will likewise have been stopped. The lastclosed auxiliary contacts 10 of relay R, by mentioned cutter motor may thereupon be conductor 39 through normally closed constopped by depressing the stop push-button tacts 18 and 17 of oveirload relays 0L, and switch 28 or .26, as the case may be, therethence throu h the right-hand overload reby interrupting the maintaining circuit of lay coil to ine L Switch S thereupon switch S or S respectively.

closes to complete the line connections for It is to be understood that any of the motor M. Switch S upon closure of its motors M, M or M may be stopped at will auxiliary contacts 14 provides a maintainby depressing the respective push-button 1 ing circuit for itself, said circuit extending switches 24, 26 or 28, whereas the means from line L by conductor 40 through the aforedescribed will operate to insure stopleft-hand overload relay coil, through the pmg of the feed motor M upon stopping of left-hand main contacts of switch S and one or more of the cutter motors.

auxiliary contacts 14, by conductor 41 In the normal operation of the system 3 through push button switch 24, and thence by the manual control means, all of the to line L as previously traced. cutter motors will be started by closing the Switch S is also provided with normally respective push-button switches 27, 25; and open auxiliary contacts 11 which are adapted thereafter the feed motor will be started by upon closure thereof to preset the energizclosing the push-button switch 23. Howing circuit of relay R for completion upon ever, if the feed motor should be intentiontemporary closure of either orboth sets of allyor inadvertently started prior to startauxiliary contacts 12 and 13 of switches ing of any or all of the cutter motors, the S and S respectively. lhus upon the 00- former will be automaticall stopped during currence of an overload upon motor M one closure of switches S or through temor both of the overload relay contacts 21 porary closure of auxiliary contacts 12 or and 22 will be opened, thus interrupting the 13, respectively. Such closure of auxiliary aforedescribed maintaining circuit of switch contacts 12 or 13 completes the energizing S whereas the latter in opening will efcircuit of relay R, whereas the latter in closfect transient engagement of its auxiliary ing efiects opening of its. auxiliary contacts contacts 13 to complete the energizing circuit 10 to interrupt the energizing circuit ofof relay R. Said circuit may be traced switch S with consequent stopping of motor from line L by conductors 29 and 42 M as aforedescribed. Moreover, in stopping through said contacts 13, by conductors 43 the system as a whole the motor M is preferand 44 through the win a g of relay R, by ably first stopped by depressing the pushnecaeaa button 24, whereupon the motors l and M are stopped by depressing the respective push-button switches 26 and 28. On the other hand if either or both or" the pushbuttons 26 and 28 are de ressed while motor M is still in operation tile-means heretofore described acts automatically to efiect stopping of the latter.

It will be noted that circuit of motor M provide an additional safety feature, inasmuch as the same will act to interrupt the energizing circuit of switch S in the event of an overload upon said motor, such as might occur if relay R failed to operate properly upon stopping of one or both of the cutter motors.

The control switches and relays employed may be of simple and standard construction, as will be obvious.

l fhat T claim and Letters Patent of the United States is:

1. The combination with an electromagnetically operable switch, of an energizing circuit therefor, and means for completing said energizing circuit, said means comprising a second electromagnetically operable desire to secure by switch having auxiliary contacts which are open in the opened and closed position of said last-mentioned switch but adapted to be temporarily closed during closing or opening of the latter.

2. The combination with an electromagnetically operable switch, of an energizing circuit therefor, means for completing said energizing circuit, said means comprising a second electromagnetically operable switch having auxiliary contacts which are open in the opened and closed position of said lastmentioned switch but adapted to be temporarily closed during closing or opening of the latter, and means adapted upon closure of said first-mentioned switch to pro vide a maintaining circuit therefor.

3. The combination with a plurality of separately operable driving motors, of electroresponsive switches for respectively con trolling the energizing circuits of said motors, means for interrupting the energizing circuit of one of said motors upon interruption of the energizing circuit of another of the same, said means comprising an electroresponsive relay adapted upon operation thereoi to interrupt the energizing circuit of one of said switches, and auxiliary contacts carried by another of said switches and adapted upon opening of the latter to efiect operating energization of said relay.

l. The combination with a motors, of individually operable electroresponsive control switches therefor, means tor rendering one or said switches subject to control by another or" the same under given conditions, said means comprising an electroresponsive relay and auxiliary contacts on said switches adapted when simultanerelays 0L in the plurality of "gization of one of having normally closed ously closed to efiect operating energization of said relay, and normally closed auxiliary contacts on said relay adapted when opened to eilect interruption of the energizing c'ircuit of one of said switches.

5. The combination with a plurality of motors, of individually operable electroresponsive control switches therefor, means for rendering one of said switches subject to control by another of the same under given conditions, said means comprising an electroresponsive relay and auxiliary contacts on said switches adapted when simultaneously closed to efiect operating energization' of said relay, all of said auxiliary contacts being normally open but certain of the same being adapted for temporary closure during opening of their respective switches, and normally closed auxiliary contacts on said relay adapted when opened to effect interruption of the energizing circuit of one of said switches.

6. The combination with a plurality of electric motors, of individually operable electroresponsive control switches therefor, and means for insuring against operation of one of said motors during starting of other of the same, said means comprising an electroresponsive relay controlling the energizing circuit of one or" said switches, and auxiliary contacts on a plurality of said switches adapted to control the energizing circuit ofsaid relay.

7. The combination with a plurality of electric motors adapted to be operated jointly, of means for insuring against operation of one of said motors during starting of other of the same and for effecting stopping of said one of said motors upon stopping of other of the same, said means comprising a plurality of electror'esponsive switches for individually controlling said motors, an electroresponsive relay having normally closed contacts controlling the energizing circuit of one of said switches, and normally open auxiliary contacts on other of said switches adapted to be temporarily closed during opening or closing of the latter to thereby control the energizing circuit of said relay.

8. The combination with a lurality of electric motors of control me "cs therefor comprising individually operable electroresponsive control switches for the respective motors and overload relays having normally closed contacts included in th energizing circuits of the respective switches, manually operable means for completing the energizing circuits of said sw tches respectively, and means for insuring against enersaid switches during initial energization of other of the same, said means comprising an electroresponsive relay contacts included in the energizing circuit of one of said switches,

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and normally open contacts carried by a opening of the auxiliary contacts of the plurality of said switches and adapted when latter. jointly closed to complete the energizing 11. In a controller for woodworking macircuit of said relay. chines and the like, the combination with a 55 9. The combination with a plurality of plurality of electric motors, electroresponelectric motors, of control means therefor sive switches for controlling the circuits of comprising individually operable electrosaid motors respectively, manually operable responsive control switches for the respecmeans, for efiecting energization and detive motors and overload relays having nori ener ization of said switches individually to mally closed contacts included .in the enerat will, means for insuring against energizagizing circuits of the respective switches, tion of one of said switches during initial manually operable means for completing the energization of other of the same and for energizing circuits of said switches respecefiecting de-energization of said one of said tively, and means for insuring against enerswitches upon de-energization of other of as gization ofone of" said switches during inithe same, said means comprising an electrotial energization of other of the same, said responsive relay having normally closed conmeans comprising an electroresponsive relay tacts included in the energizing circuit of having normally closed contacts included in one of said switches, and normally open the energizing circuit of one of said switches, auxiliary contacts on said last-mentioned m and normally open contacts carried .by a switch and on other of said switches and plurality of said switches and adapted when adapted when jointly closed to complete the jointly closed to complete the energizing energizing circuit of said rela circuit of said relay, certain of said auxil- 12. In a controller for wood woi'kingmaiary contacts being normally open in the chines and the like, the combination with a Z opened or closed position of their respective plurality of electric motors, electroresponsive switch but adapted for temporary closure switches for controlling the circuits 1 of during closing or openingof the latter. said motors respectively, manually operable 10. The combination .with a plurality of means for effecting energization and deelectric motors, of control means therefor energization of said switches individually 90 comprising individually operable electroat will, means for insuring against energires onsive switches for the respective motors zation of one of said switches during inian overload relays having normally closed tial energization of other of the same and contacts included in the energizing circuitsv for effecting de-energization of said one of of the respectiveswitches, manually operable said switches upon de-energization of other 85 means for controlling the energizing cirof the same, said means comprising an eleccuits of said switches respectively, and troresponsive relay having normally closed means forefiecting interruption of the enercontacts included in the energizin circuit gizing circuit of one; of said switches upon of one of said switches, normal y open interruption of the energizing circuit of auxiliary contacts on said last-mentioned 90 other of the same, said means comprising switch and on other of said switches and an electroresponsive relay having normally adapted when jointly closed to complete the closed auxiliary contacts adapted to be inenergizing circuit of said relay, and overcluded in the energizing circuit of oneof load relays having normally closed contacts said switches, normall open auxiliary conincluded in the energizing circuits of certain 95 tacts carried by said ast-mentioned switch, of said switches and adapted under given and auxiliary ont cts Ca ri d by other of conditions to automatically interruptsaid said switches and adapted for temporary ir uits, closure during opening of the latter, said In witness whereof, I have hereunto sub-- auxiliary contacts of said switches when scribed my name; f jointly closed beingladapted to complete the energizing circuit of said relay to efiect RICHARD B, w

IPER. 

